Detailed study on effects of gate voltage, frequency and temperature on dielectric properties of Cu/PAr/n-CdS/SnO₂ MIS Schottky diode

In this paper, CdS based metal–insulator–semiconductor (MIS) diode was fabricated by using the Polyarylate (PAr) film as insulator dielectric on transparent conductive glass substrate. The dielectric parameters such as dielectric constant (${ϵ}^{{}^{\prime }}$), loss (ϵ), loss tangent (tan δ), ac conduc-tivity (σ _AC) and complex modulus ($M^{{}^{\prime }}$, $M^{{}^{\prime \prime }}$) of the MIS Schottky diode were examined as a function of signal frequency, gate voltage and temperature. The detailed analysis revealed the interface states at the CdS/PAr junction and the characteristics of these interface states in the examined frequency range. The value of the angular frequency exponent (S) and the corres-ponding temperature dependence of σ _ac indicate the hopping mechanism which agrees with the CBH model. The barrier height between the neighbouring states is determined as 47 meV for the temperature range studied. The temperature dependence of ΔV _FB verifies the thermally active behaviour of interface states which decrease from 117 to 41 meV with increasing temperature. (paper)